The invention relates to a exhaust gas system with a particulate filter and a burner for regeneration of the particulate filter, the burner being equipped with a fuel mixing nozzle and with a flame tube extending at least in part into the exhaust gas system and being able to be acted upon by the exhaust gas.
In so-called full flow burner exhaust gas systems, the burner is so positioned in the exhaust gas tube that the exhaust gas flows partly around the burner and at the outlet of the burner is mixed with the hot gases. The advantage of this design is that the burner may be lit even during operation of the engine in which exhaust gases are being expelled. A system of this type is described in the European patent publication 306 743A2, in which the exhaust gases flow in an annular gap perpendicularly onto a flame tube of the burner, sweep along the flame tube in the longitudinal direction and the finally in a transverse flow mixer are mixed with the hot gases coming from the burner. For this purpose there is a hot gas outlet opening at the end face of the flame tube and there is a baffle plate positioned at a distance from this opening and opposite to it, such means deflecting the axially merging hot gases radially, before they are mixed with the exhaust gases.
In the case of such a design it is possible for unfavorable flow conditions to arise in which the hot gases which come from the radial outlet ring formed between the baffle plate and the end wall of the flame tube, are not evenly distributed, so that local, overheated currents may cause damage to the filter. In this respect it is possible furthermore for unburned fuel from the burner to be ignited at the radial outlet and to burn with the residual oxygen, contained in the exhaust gas, as s secondary flame, which has a larger size, that is to say a large flame length and may also cause local damage to the soot filter positioned relatively close to the burner. In such cases the particulate filter has to be placed at a considerable distance from the burner for safety reasons, this increasing the overall size and making the system more expensive.